Subminiature connector for coaxial cables



Dec. 15, 1964 A. E. POWELL SUBMINIATURE CONNECTOR FOR COAXIAL CABLES Filed Jan. 24, 1962 2 Sheets-Sheet 1 INVENTOR.

A ALBERT 5 POWELL p mx 5/ A. E. POWELL SUBMINIATURE CONNECTOR FOR COAXIAL CABLES Dec. 15, 1964 Filed Jan. 24 1962 2 Sheets-Sheet 2 m 246 /4/ a 44662 3/ m 32 INVENTOR. ALBERT E. POWELL 4 mm! l w 'g A TTORNEX United States Patent Ofiice 3,16l ,453 Patented Dec. 15, 1964 Filed Jan. 24, 1962, Ser. No. 168,397 2 Claims. (Cl. 339--1i7) The present invention relates to improved coupling means for use with coaxial cables and more particularly to coaxial cables of minimal dimensions wherein the outer conductor is of solid metal, in contradistinction to braided outer conductors in coaxial cables.

The growth of the field of subminiaturization, involving the use of components verging on the microscopic, raises problems not anticipated in conventional electronic components, even as to those which can loosely be called subminiaturized. Thus, in the art of providing connectors for coaxial cables it is well known to provide coupling means for cables having an outer conductor of braided or woven conductor material, usually copper. Generally speaking, the flexible outer braid is separated from the insulator layer and physically clamped to the connector. However, the need for miniaturization has created a demand for coaxial cable of such small dimension that a layer of metal a few thousandths of an inch thick is deposited over the insulator layer to form the outer conductor; hence it is manifestly impossible to separate the outer metallic layer from the insulator without destruction of the cable itself. It may be added that the need for subminiature cable is so great that it has been necessary to develop new manufacturing techniques to apply an outer conductive layer of copper so thin that an added coating of lead has to be applied about this to provide structural solidity, to prevent the copper layer from being rubbed off or otherwise removed. it will therefore be apparent that radically difierent means must be employed to form a connector for cable of this type, and means applicable for a braided type coaxial cable are not suitable.

The design of a subminiaturized device is necessarily dependent on the state of the art of manufacturing the individual components involved, and the techniques presently available. As the device of this invention is described hereinafter, it will be appreciated that the simple, aixal plug in mating configuration employed is far more desirable than the use of a threaded engagement. The machining of extremely fine screw threads is costly and subject to a high rate of production rejects. The fragile fine screw type couplings are subject to the stripping of threads and have the added drawback of twisting the in dividual cables during connection or dismantling, with attendant risk of rupturing the connections. The present device envisages an extremely simple snap connection with the use of detents, whereby the device is brought together in the assembled condition by translational movement rather than by twisting of the cables. The present embodiment of the invention employs a thread only for the original assembly of connector to cable, hence the thread is used only once. For operational use, there is provided a simple connection of maximum reliability, as set forth hcreinbelow.

It is therefore a primary object of the present invention to provide an improved connector for subminiature coaxial cables of the solid outer conductor type.

It is a further object of the present invention to provide connector means having simplified means for manufacture and assembly, and having maximum freedom from failure or disconnect, consonant with small physical size.

It is, a particular object of the present invention to provide connector means where there is no lateral deformation of the cable elements, wherein clamping, flaring, compression or other physical tampering with the cable is avoided.

Other objects and advantages of the present invention will be apparent or will be pointed out with greater particularity in the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective full size showing of the con nector.

FIG. 1a is a perspective similar view to FIG. 1, but enlarged about ten times.

FIG. 2 is an enlarged cross-section taken along line 2-2 of FIG. la.

FIG. 3 is an exploded view of the device.

Referring more particularly to the drawings, there is shown in PEG. 1 an embodiment of the present invention characterized generally by the numeral Ill, wherein means are provided for connecting terminal portions to coaxial cables 12 and 14. These cables comprise an inner conductor 1-5, a plastic insulation 17, such as Teflon or the like, formed about this inner conductor, and an outer conductor 18 of a solid metallic conductor material, as distinguished from the braided outer construction of the usual coaxial cable. It should be noted that it is envisaged that the connector of the present invention be employed with coaxial cables of minimal dimension, wherein the inner conductor has a diameter of 0.008 inch to 0.011 inch and the outer conductor ranges in diameter from 0.025 inch to 0.032 inch. The outer conductor is usually a copper layer formed by being drawn over the insulator during the extrusion or the insulator, with a gold film plated above the copper, or by plating a copper layer over the plastic with a lead protective outer covering, providing relative flexibility to the cable.

Such cable can be provided with an external layer of insulation where desired, but for purposes of illustration this is not shown in the present embodiment.

The connecting means envisaged in the present invention may be broadly characterized as an assembly for providing means for axially mating the inner conductors, means for coaxially mating the inner insulators, and means for coaxially mating the outer conductors, to provide the proper impedance match between the two cables, 12, 14. Such a connector preserves the configuration of a conductive central portion, provided here by contacts 2tla2lb. An insulator portion concentric with this is formed by insulators 24a, 24b, 26a, 26!). An outer conductive shell is formed by metallic sleeves Elia-23b and connectors Killer-3%. ltwill be noted that the coaxial configuration of these elements provide an optimum impedance match for the two coaxial cables that are to be connected.

The outer conductor connecting means comprise metal sleeves Zen-28b, provided with axial bores 30 of a diameter corresponding to that of the outer conductor 13 of the cables. These sleeves are soldered over the end portions of the cables 12 and 14, respectively, hole 31 being provided for inspection purposes. Sleeves 2311-2812 have externally threaded end portions 32 adapted to threadedly engage connector portions 3tla3tlb, each of which is provided with an internally threaded end portion 34. It will be noted that sleeves 2841-2811 are provided with a reduced bore portion 2 3x143!) defining inner shoulders 41. These shoulders abut against the trimmed portion of outer conductor 13, and the reduced bores register with insulation 1? of each cable, respectively. Connectors filial-3% have an overlapping mating configuration, being retained in the assembled position by split ring whereby female member 3% has a reduced shell portion 38 which abuts with the corresponding undercut segment 40 of the connector Silo. The split ring is assembled in the usual manner. That is, a small amount of clearance is provided between the ID. of split ring Cl 36 and the annular groove of member Etta in which the ring is seated. When member 3% is assembled the ring is compressed, taking up the clearance, and then allowed to snap back into an opposing groove in member 39b. Thus the split ring is simultaneously engaged in the two opposed grooves thereby preventin" relative axial motion between members 3-tla and 3%. In the assembled condition, connectors 3M4) define a hollow cylindrical member having bore 42. Within this bore are concentrically retained the insulators and contacts, in a manner to be described hereinbelow. Insulators Z ta-23 5b are each provided with an axial bore l3 corresponding to the diameter of the inner insulation 17 of cables 12, 14. An internal shoulder 41 is formed at the ends of metal sleeves Eda-23b to register with a shoulders Sin-31b formed by the juncture of cable insulation 17 and cable outer conductor l8.

insulators 245F241: have diameters corresponding to that of bore 42 formed by connectors Sbafib, and are formed with an external shoulder 4s and collar These register in mating axial configuration with insulators Zea- 2611, each of which has a cylindrically hollow end portion 5% adapted to seat on collars 4-8 and abut shoulders respectively. Insulator a is of cylindrical hollow configuration provided with an inner radial flange 52. abutting axially with outer flange 55 formed on contact 20a and is of outer diameter corresponding to that of bore 42. Insulator 26b is of stepped cylindrical configuration having an external wall portion (54 formed of diameter to register with bore 42, and shoulder 55' registering axially with inner flange 56 formed on metal connector 39b. Reduced external wall portion 58 of insulator 24b is adapted to abut inner bore 66 of insulator 24a being retained axially by internal ridge 52 formed on insulator 24a. It will thus be noted that the general overall configuration of insulators 22 la24b and Zfiafib is that of a hollow cylindrical member being retained against axial displacement by the mating configuration of the separate insulators and against lateral displacement by the outer metal shells dun-36b.

Contact members Zlia and Zllb are of mating configuration and are connected respectively to the inner conductors 16 of cables l2, 14, by means of axial passages 62 formed in each contact, in which the respective inner conductors 16 are soldered, hole 64- being conveniently formed for inspection (see FIG. 3). In the assembled position, FIG. 1, contacts Etta and 2% registered in mating relation, being retained against axial displacement by the configuration of the insulators disposed concentrically about them. Thus, it will be noted that shoulder as of contact member Zita abuts collar 43 of insulator 24a and shoulder 70 of contact Lilla abut inner radial flange 52 of insulator Ztia. Similarly, shoulder 72 of contact 2% abuts collar of insulator 24b and shoulder 74 of contact 20b abuts internal shoulder '76 formed on insulator 265. It will also be observed that contacts Ella-29b are constrained against lateral or transverse movement by the internal diameter configuration of insulators 24-241), 26-265. Thus, the central outer wall portion 53 of contacts 2lla20b abut the inner Walls t ll, fill of insulators 26a and 26b, respectively, and reduced wall portions 52 of contacts Zlla-Ztlb register with the bore 43 of insulators 2441-241), respectively. It will thus be apparent that these contact members are captured against lateral and axial displacement.

In assembling the device of the present invention, a portion of the solid outer conductor 13 of the cable is trimmed away, exposing a terminal or end portion of the insulation 17. Metal sleeves Eda-23b are first soldered onto outer conductors 18, inspection opening 31 being provided in the sleeve for checking the soldering. It will be noted that reduced diameter Z ,-a2b of sleeve 28a- P-Sb, gives a positive location for the end of the coaxial outer conductor, namely at shoulder Eta-31b, also providing by its precision bore for the carry over from the coaxial cable to the connector for maintenance of impedance at this point. Insulators Z la-Zdb are then disposed abutting the respective end section of each metal sleeve, and in contact with the exposed insulation portion of the cable. Next, the contact members Zen and 26b are placed in position, with each of the inner conductors in being placed in passage 62 of the contact members respectively, which are then soldered, utilizing inspection openings 64 for checking purposes. insulators 26a-26b are placed in position respectively about contacts Etta-29b, abutting against these contacts and against insulators 24a- Zdb, as explained heretofore, in retaining configuration.

Outer connector shells Cilia-3% are then screwed into position over metal sleeves 28a28b, respectively, by

means of internal threads 34 in registry with external threads 32 of the metal sleeves. in the assembled position, rim of connector Eula retains the end portion of insulator 26a and similarly, internal flange S6 of connector Etlb retains insulator 26b by bearing against shoulder 54. The device is then connected by simple axial movement, whereby prong 84 of contact 20a is engaged in receptable as of contact 291), and simultaneously members lli and 38 of connectors Sun-30b register, being clamped securely by the action of split ring 36. It will be noted that the device of the present invention provides a connector device wherein none of the components of the cables has been subject to any axial or lateral distortion, that there has been no crimping, pressure, or compression on any of the conductors of the insulator of the coaxial cables. Moreover, due to the minute dimensions of the parts involved, it will be apparent that the simple snap feature will provide trouble-free operation Where the use of a threaded collar to join the two sections would prove impractical in the present instance.

There has been disclosed heretofore the best embodiment of the invention presently contemplated and it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

'1. A subminiature assembly for releasably connecting first and second coaxial cables each of which has an inner conductor, an inner insulator concentrically disposed about the inner conductor and an unbraided, solid outer conductor of minimal wall thickness integral with the outside surface of the inner insulator, said cables being further defined by the end portions of the inner insulator and outer conductor being trimmed back to expose th next lower, concentric layer; said assembly comprising:

(a) a metallic contact pin and a metallic contact receptacle coaxially secured to the respective inner conductors of the first and second cables, said contact pin having a solid end portion opposite the exposed end of the inner conductor, said contact receptacle having an axial bore which defines a continuously surfaced end portion opposite the exposed end of the second inner conductor, said contact pin and contact receptacle being adapted to mate with each other in the assembled condition;

(b) first and second insulating sleeves tightly disposed about at least a portion of each of the respective contact pin and contact receptacle of the first and second cables proximate the exposed ends thereof, said first insulating sleeve also having an enlarged, concentric bore spacedly disposed about a portion of said contact pin extending from the end of the first inner conductor, said second insulating sleeve being tightly disposed about the entire length of said contact receptacle, said first and second insulating sleeves having a substantially uniform, continuous outside diameter in the assembled condition, said insulating sleeves being provided with integral, internal shoulders adapted to restrain said contact pin first and second metallic sleeves coaxially secured to the respective outer conductors of the first and second cables;

(d) third and fourth metallic outer sleeves coaxially joined to said first and second metallic sleeves, respectively, each of said third and fourth metallic outer sleeves having a first axial bore which deductor being trimmed back to expose the next lower, concentric layer;

second cables proximate the exposed ends thereof, said first insulating sleeve also having an enlarged, concentric bore spacedly disposed about a portion of said first pin opposite the end of said first inner conductor, said second insulating sleeve being tightly disposed about the entire length of said contact receptacle, said first and second insulating sleeves having a substantially uniform, continuous outside diameter in the assembled condition, said insulating fines a continuously surfaced end portion coaXia 10 sleeves being provided with integral, internal shoulwith and opposite the trimmed-back ends of the reders adapted to restrain said contact pin and conspective first and second cable outer conductors, said tact receptacle from axial motion relative to their fourth metallic sleeve having a second coaxial bore respective cables; adapted to mate with the end portion of said thi d ((1) first and second metallic sleeves coaxially secured metallic sleeve whereby a substantially uniform outto said respective outer conductors of said first and side diameter is provided in the assembled condisecond cables; tion of said metallic sleeves; and (e) third and fourth metallic outer sleeves coaxially (e) annular retaining means adapted to releasably coujoined to said first and second metallic sleeves, re-

ple said first and second metallic sleeves upon axial spectively, each of said third and fourth metallic motion Of one Of said metallic sleeves in the direcsleeves having a first axial bore which defines a tion of the outer of said metallic sleeves. continuously surfaced end portion coaxial with end 2. A subminiature cable and conductor assembly comopposite the trimmed-back ends of said respective prising: first and second cable outer conductors, said seefirst and Second Coaxial Cables h f Which has ond metallic sleeve having a second coaxial bore an inner conductor, an inner insulator concentricaladapted to mate with said end portion of said first 1y disposed about said inner conductor and an unmetallic sleeve whereby a substantially uniform outbraided, solid outer conductor of minimal wall thickside diameter is provided in the assembled condiness integral with the outside surface of said inner tio of said metallic sleeves; and insulator, said cables being further defined by the (f) annular retaining means adapted to releasably couend portions of said inner insulator and outer conple said first and second metallic sleeves upon axial motion of one of said metallic sleeves in the direction of the other of said metallic sleeves.

(b) a metallic contact pin and a metallic contact receptacle coaxially secured to the respective inner conductors of said first an dsecond cables, said contact pin having a solid end portion opposite the ex- References tilted by the Examiner UNITED STATES PATENTS 2 209 152 7/ Daniels.

posed end of said inner conductor, said contact 16- ceptacle having an axial bore which defines a con- 2 33? 3& Tohafnesen Z tinuous surfaced end portion opposite the exposed Z /37 a 33* 177X end of said second inner conductor, said contact 40 $5384 3/57 v/1 CkeSSer 339*177X pin and contact receptacle being adapted to mate g a- 333 5;?

' th t1 b with each 0 er in lo assem led condition 3,054,981 9/62 Malek et a1 339*177 (c) first and second insulating sleeves tightly disposed about at least a portion of each of said respective Q- contact pin and contact receptacle of said first and JOSEPH Puma); Emmmel? 

1. A SUBMINIATURE ASSEMBLY FOR RELEASABLY CONNECTING FIRST AND SECOND COAXIAL CABLES EACH OF WHICH HAS AN INNER CONDUCTOR, AN INNER INSULATOR CONCENTRICALLY DISPOSED ABOUT THE INNER CONDUCTOR AND AN UNBRAIDED, SOLID OUTER CONDUCTOR OF MINIMAL WALL THICKNESS INTEGRAL WITH THE OUTSIDE SURFACE OF THE INNER INSULATOR, SAID CABLES BEING FURTHER DEFINED BY THE END PORTIONS OF THE INNER INSULATOR AND OUTER CONDUCTOR BEING TRIMMED BACK TO EXPOSE THE NEXT LOWER, CONCENTRIC LAYER; SAID ASSEMBLY COMPRISING: (A) A METALLIC CONTACT PIN AND A METALLIC CONTACT RECEPTACLE COAXIALLY SECURED TO THE RESPECTIVE INNER CONDUCTORS OF THE FIRST AND SECOND CABLES, SAID CONTACT PIN HAVING A SOLID END PORTION OPPOSITE THE EXPOSED END OF THE INNER CONDUCTOR, SAID CONTACT RECEPTACLE HAVING AN AXIAL BORE WHICH DEFINES A CONTINUOUSLY SURFACED END PORTION OPPOSITE THE EXPOSED END OF THE SECOND INNER CONDUCTOR, SAID CONTACT PIN AND CONTACT RECEPTACLE BEING ADAPTED TO MATE WITH EACH OTHER IN THE ASSEMBLED CONDITION; (B) FIRST AND SECOND INSULATING SLEEVES TIGHTLY DISPOSED ABOUT AT LEAST A PORTION OF EACH OF THE RESPECTIVE CONTACT PIN AND CONTACT RECEPTACLE OF THE FIRST AND SECOND CABLES PROXIMATE THE EXPOSED ENDS THEREOF, SAID FIRST INSULATING SLEEVE ALSO HAVING AN ENLARGED, CONCENTRIC BORE SPACEDLY DISPOSED ABOUT A PORTION OF SAID CONTACT PIN EXTENDING FROM THE END OF THE FIRST INNER CONDUCTOR, SAID SECOND INSULATING SLEEVE BEING TIGHTLY DISPOSED ABOUT THE ENTIRE LENGTH OF SAID CONTACT RECEPTACLE, SAID FIRST AND SECOND INSULATING SLEEVES HAVING A SUBSTANTIALLY UNIFORM, CONTINUOUS OUTSIDE DIAMETER IN THE ASSEMBLED CONDITION, SAID INSULATING SLEEVES BEING PROVIDED WITH INTEGRAL, INTERNAL SHOULDERS ADAPTED TO RESTRAIN SAID CONTACT PIN AND CONTACT RECEPTACLE FROM AXIAL MOTION RELATIVE TO THEIR RESPECTIVE CABLES; (C) FIRST AND SECOND METALLIC SLEEVES COAXIALLY SECURED TO THE RESPECTIVE OUTER CONDUCTORS OF THE FIRST AND SECOND CABLES; (D) THIRD AND FOURTH METALLIC OUTER SLEEVES COAXIALLY JOINED TO SAID FIRST AND SECOND METALLIC SLEEVES, RESPECTIVELY, EACH OF SAID THIRD AND FOURTH METALLIC OUTER SLEEVES HAVING A FIRST AXIAL BORE WHICH DEFINES A CONTINUOUSLY SURFACED END PORTION COAXIAL WITH AND OPPOSITE THE TRIMMED-BACK ENDS OF THE RESPECTIVE FIRST AND SECOND CABLE OUTER CONDUCTORS, SAID FOURTH METALLIC SLEEVE HAVING A SECOND COAXIAL BORE ADAPTED TO MATE WITH THE END PORTION OF SAID THIRD METALLIC SLEEVE WHEREBY A SUBSTANTIALLY UNIFORM OUTSIDE DIAMETER IS PROVIDED IN THE ASSEMBLED CONDITION OF SAID METALLIC SLEEVES; AND (E) ANNULAR RETAINING MEANS ADAPTED TO RELEASABLY COUPLE SAID FIRST AND SECOND METALLIC SLEEVES UPON AXIAL MOTION OF ONE OF SAID METALLIC SLEEVES IN THE DIRECTION OF THE OUTER OF SAID METALLIC SLEEVES. 